Such motors are used for a variety of purposes and have great advantages because, among other things, their rotation speed or RPM is controllable. It is desirable for power supplies for such motors, and for similar consuming devices with low wattage, to be adaptable for use in different nations with differing power network voltages and frequencies, for example from 70 to 260 volts and for 40 to 100 cycles per second (Hertz). Naturally, for many nations, one must also swap in a different plug configuration. Such highly adaptable power supplies have hitherto been expensive.
Adaptable power supplies are common in computers today, i.e. the so-called "international version" of a computer can be plugged into any power network having AC voltage between 110 and 260 V. The higher voltages cause some difficulty. Computers are devices with a power demand from about 30 to 100 watts, while small motors often have a power demand of 1 or 2 watts, so that many of the solutions known for computers would be too expensive.